JPH05320299A - Preparation of aqueous emulsion of polyurethane-acrylic resin - Google Patents

Abstract

PURPOSE:To obtain the emulsion excellent in water resistance, durability and solvent resistance, capable of forming a high-gloss coating film, and high in workability, by emulsion polymn. of ethylenically unsatd. monomers comprising an acrylic monomer as the main component in the presence of a specific self- emulsifiable modified prepolymer. CONSTITUTION:A urethane prepolymer having NCO groups in the molecular terminals thereof is reacted with an ethylenically unsatd. monomer contg. an OH group at an OH/NCO ratio of 0.3 to 0.6 to obtain a self-emulsifiable modified prepolymer having ethylenically unsatd. bonds and NCO groups in the molecule thereof. An aq. dispersion of 100-1,000 pts.wt. polymerizable mixture of ethylenically unsatd. monomers containing an acrylic monomer as the main component is emulsion-polymerized in the presence of 100 pts.wt., on a solid basis, of the self-emulsifiable modified prepolymer to obtain the objective emulsion excellent in water resistance, durability and solvent resistance (alcohol resistance), capable of forming a high-gloss coating film, and high in workability.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION Industrial field of polyurethane / acrylic resin obtained by the practice of the present invention is wood, metal,
It is useful as a coating material for base materials such as plastics, fibers, leather, and paper, and as various finishing agents.

[0002]

2. Description of the Related Art Water-based polyurethane paints have been used instead of solvent-type polyurethane paints from the 1960s in view of environmental hygiene. This water-based polyurethane paint can be applied transparently or colored and gives a film with excellent gloss and abrasion resistance. This water-based polyurethane paint is mainly used as a coating material for woodworking products and flooring materials and a processing material for fibers.

However, this film has been desired to be further improved in terms of the balance between solvent resistance, alkali resistance and water resistance. As a means for improving such drawbacks, generally, a method of blending a self-emulsifying polyurethane with a crosslinking agent such as polyfunctional aziridine, or a (meth) acrylic acid alkyl ester copolymer aqueous emulsion or a (meth) acrylic acid / styrene copolymer aqueous emulsion Is used [Technical data sheet of Gunze Sangyo Co., Ltd. "Polyurethane for sunker coating"]. Among them, the method of using a crosslinking agent is inferior in workability such as a two-liquid type or heating at 100 ° C. or more is required for proceeding crosslinking. Further, it is pointed out that the blending method has a drawback that the coating film becomes cloudy as shown in the same data sheet and Comparative Examples 1 and 2 of JP-A-59-138211.

As a means for preventing such a film from fogging and improving the hardness of the film, a urethane prepolymer obtained from diisocyanate and a polyol having a molecular weight of 200 to 4000 has a molecular weight of 3 according to JP-A-59-138211.
2 to 40 parts by weight of polyurethane cross-linked with a chain extender for urethane of 00 or less is mixed with 100 parts by weight of ethylenically unsaturated monomer such as methyl methacrylate, butyl acrylate and styrene, and the polymerizable solution is mixed with water. A method of producing a polyurethane-acrylic resin aqueous emulsion by dispersing the resulting solution in an emulsion and emulsion-polymerizing the same was proposed.

[0005]

However, according to the above method, an aqueous emulsion which gives a transparent film having excellent water resistance and hardness can be obtained, but the problem is that the film is inferior in solvent resistance and durability. However, the desks and corridors that are generally coated with polyurethane-based paint have a problem that stains are likely to be generated by alcohols that are drunk at banquet seats, and solutions to them have been desired.

The present invention is not only water resistant but also durable.
An object of the present invention is to provide a method for producing a polyurethane / acrylic resin aqueous emulsion which gives a film having excellent gloss also in solvent resistance (alcohol resistance) and has high workability.

[0007]

In order to achieve the above-mentioned object, a method for producing an emulsion, which is a feature of the present invention, comprises a urethane prepolymer having an isocyanate group at a terminal and an ethylenically unsaturated monomer having a hydroxyl group. Are reacted at an equivalent ratio (-OH / -NCO) of the isocyanate group of the former prepolymer and the hydroxyl group of the latter monomer to 0.3 to 0.6 to give ethylenic unsaturation in the molecule. A self-emulsifying modified prepolymer having a bond and an isocyanate group is obtained, and in the presence of 100 parts by weight of a solid content of the self-emulsifying modified prepolymer, an ethylenic unsaturation containing an acrylic monomer as a main component is obtained. It is formed by emulsion-polymerizing an aqueous dispersion of a polymerizable mixture in which the monomers are mixed in a proportion of 100 to 1000 parts by weight. Further, in order to form a film that is tough and has excellent durability, an isocyanate group is added to the end. In a urethane prepolymer having a nate group, an ethylenically unsaturated monomer having a hydroxyl group is added in an equivalence ratio (-OH / -NCO) of the isocyanate group of the former prepolymer to the hydroxyl group of the latter monomer of 0. 3-0.
To give a self-emulsifying modified prepolymer having an ethylenically unsaturated bond and a -NCO group in the molecule, and in the presence of 100 parts by weight of the solid content of the self-emulsifying modified prepolymer, Ethylenically unsaturated monomer mixture of the following (a) to (d) (a) Carbonyl group- or aldehyde group-containing ethylenically unsaturated monomer 1 to 20% by weight (b) Methacrylic acid alkyl ester (of alkyl group Carbon number is 1 to 4) 25 to 75% by weight (c) Acrylic acid alkyl ester (carbon number of alkyl group is 1 to 8) 10 to 55% by weight (d) Other ethylenically unsaturated monomer 0 to 40 Emulsifying an aqueous dispersion of a polymerizable mixture obtained by mixing 100% by weight of 100% by weight (however, the sum of components (a), (b), (c) and (d) is 100% by weight). Carbonyl obtained by polymerization Or aldehyde group-containing polyurethane-acrylic resin aqueous emulsion (A), the hydrazide group (-NH
-Crosslinking agent (B) having two or more NH ₂ ) is blended.

[Urethane Prepolymer Having an Isocyanate Group at the Terminal] Examples of the urethane prepolymer having an isocyanate group at the terminal include those described in Journal of Coating Technology, vol. 58, No. 738, 19
July 1986, pages 49-51 and JP-A-59-13821.
No. 1, which has a molecular weight of 200-400.
A urethane prepolymer obtained by reacting a polyol of 0 with a polyisocyanate compound having two or more isocyanate groups (-NCO) is further polymerized with a chain extender for urethane to obtain a urethane prepolymer having an isocyanate group at the end. , Which can be self-emulsifying urethane prepolymer by ionizing it with acid or alkali and

[0009]

[Chemical 1]

A urethane prepolymer having an isocyanate group at the terminal and having a nonionic group represented by the following formula, which has been polymerized with a chain extender having a polyether group represented by, can be used.

[0011]

[Chemical 2]

The polyisocyanate used as the raw material for the urethane prepolymer is an aromatic, aliphatic or alicyclic diisocyanate such as 1,5-naphthene diisocyanate or 4,4'-diphenylmethane diisocyanate.
4,4'-diphenyldimethylmethane diisocyanate, di- and tetraalkyldiphenylmethane diisocyanate, 4,4'-dibenzyl diisocyanate, 1,
3-phenylene diisocyanate, 1,4-phenylene diisocyanate, toluylene diisocyanate, chlorinated diisocyanates, brominated diisocyanates,
1,4-butylene diisocyanate, 1,6-hexane diisocyanate and xylylene diisocyanate,
Etc.

The polyols are those used in general urethane products, such as polyethers,
Any of polyesters, polyesteramides, polythioethers, polybutadiene glycols and the like can be used. As the polyethers, water, ethylene glycol, propylene glycol, glycerin, bisphenol A, and other compounds having active hydrogen are used as the starting materials, and usually ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, etc. are prepared by ring-opening addition polymerization. Be done.

Polyesters include ethylene glycol, propylene glycol, 1,3-butanediol,
1,4-butanediol, neopentyl glycol, pentanediol, hexanediol, octanediol, 2-ethyl 1,3-hexanediol, bisphenol A, diethylene glycol, dipropylene glycol, etc. Obtained by condensation with a neutral acid. Other polythioethers and polyacetals can also be used. To obtain these urethane prepolymers, the CPR of polyols is usually lowered (CPR is in accordance with JIS K1557), 3
The compounding molar ratio of polyisocyanate / polyol at the time of synthesis, which is synthesized at a reaction temperature of about 0 to 150 ° C., is 0.5 to 2.
5 mol is used.

As the chain extender, N-methyldiethanolamine, N-ethyldiethanolamine, N-oleyldiethanolamine, dimethylolpropionic acid, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,3-butylene glycol. , Tetramethylene glycol, hexamethylene glycol, 1,4-butanediol, neopentyl glycol, diaminoethane, 1,6-diaminohexane, piperazine, 2,5-
Dimethylpiperazine, 4,4'-diaminodicyclohexylmethane, 1,2-propylenediamine, hydrazine, etc., which may be used alone or in combination.

[Ethylenically unsaturated monomer having a hydroxyl group] Examples of the monomer include 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate and 2-hydroxy-3-chloropropyl. Acrylate, acryloyloxyethyl hydrogen tartrate, β-hydroxyethyl-β-acryloyloxyethyl phthalate, 1,4-butylene glycol monoacrylate,
N-methylol acrylamide, hydroxystyrene,
Vinyl alcohol, allyl alcohol, methallyl alcohol, isopropenyl alcohol, 1-butynyl alcohol, ethylene glycol monoacrylate, 1,4
-Butanediol monoacrylate or the like is used.

The reaction ratio between the urethane prepolymer having an isocyanate group at the terminal and the ethylenically unsaturated monomer having a hydroxyl group is such that the equivalent ratio of the --NCO group of the prepolymer to the --OH group of the monomer (--OH / -NCO) is 0.3 to
It is 0.6, and when emulsion polymerization is carried out using a self-emulsifying modified prepolymer having an ethylenically unsaturated bond in which all the -NCO groups have reacted with hydroxyl groups, gelation tends to occur, so it is preferably around 0.5. To

The reaction product of the urethane prepolymer and the ethylenically unsaturated monomer having a hydroxyl group has a free --NCO group, but since it reacts with active hydrogen, it is not preferable and therefore this --NCO group is used as glycerin or caprolactam. Mask with the masking agent and ionize with acid or alkali. Tertiary amines, ammonia, etc. are used as the alkali, and inorganic acids such as hydrochloric acid and organic acids such as acetic acid are used as the acid.

[Ethylene Unsaturated Monomer] As the main component of the ethylenically unsaturated monomer, an acrylate such as an alkyl acrylate or an alkyl methacrylate is used from the viewpoint of weather resistance. Besides, styrene, vinyl acetate, ethylene, acrylonitrile, acrylamide and the like may be used in combination.

Preferably, the following monomer mixtures (a) to (d) are desirable in order to make the coating film tougher and more durable. (A) Carbonyl group- or aldehyde group-containing ethylenically unsaturated monomer 1 to 20% by weight (b) Methacrylic acid alkyl ester (alkyl group has 1 to 4 carbon atoms) 25 to 75% by weight (c) Alkyl acrylate Ester (the carbon number of the alkyl group is 1 to 8) 10 to 55% by weight (d) Other ethylenically unsaturated monomer 0 to 40% by weight (the total of the monomers a to d is 100% by weight) Consists of.

The component (a) is a vinyl monomer used for introducing a crosslinkable carbonyl group or an aldehyde group into the copolymer obtained by emulsion polymerization, and contains at least one aldo group or A monomer having a double bond capable of polymerizing with a keto group, that is, a polymerizable monoolefinic aldo compound or keto compound. And as a carbonyl group

[0022]

[Chemical 3]

Of course, compounds having only are not included in the monomer. Examples of the monomer include acrolein, diacetone acrylamide, formyl styrene, vinyl alkyl ketone having 4 to 7 carbon atoms (for example, vinyl methyl ketone, vinyl ethyl ketone,
Vinyl butyl ketone), general formula

[0024]

[Chemical 4]

(Wherein R ¹ is H or CH ₃ , R ² is H or an alkyl group having 1 to 3 carbon atoms, and R ³ is 1
An alkyl group having 3 to 3 carbon atoms, and R ⁴ represents an alkyl group having 1 to 4 carbon atoms. ) Acrylic (or methacryl) oxyalkyl propanal, acetonitrile acrylate, diacetone acrylate, diacetone methacrylate, 2-hydroxypropyl acrylate-acetyl acetate, butanediol-1,4-acrylate-acetyl acetate, and the like. Particularly preferred are diacetone acrylamide, acrolein and vinyl methyl ketone. Two or more kinds of these monomers may be contained in the copolymer.

The component (b), a methacrylic acid alkyl ester, imparts hardness and toughness to the film, and is composed of methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, normal propyl methacrylate, and t-butyl methacrylate. , Normal-butyl methacrylate, isobutyl methacrylate, and 2-butyl methacrylate are used.

The (c) component alkyl acrylate imparts flexibility and elasticity to the film, and ethyl acrylate, propyl acrylate, normal butyl acrylate, 2-ethylhexyl acrylate, etc. are used. ..

As the component (d), unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, fumaric acid and maleic acid, acrylonitrile, acrylamide, methacrylamide, styrene, vinyl acetate, α-methylstyrene, ethylene, Examples thereof include vinyl chloride. These are used in an amount of 0 to 40% by weight in order to adjust the minimum film-forming temperature of the obtained copolymer emulsion and to introduce a functional group into the copolymer.
Used in proportion.

When the amount of the ethylenically unsaturated monomer having a carbonyl group or an aldehyde group as the component (a) is less than 1% by weight in the monomer mixture, the crosslink density of the film is low and the alcohol resistance is improved. There is no. On the other hand, if it exceeds 20% by weight, the coating becomes too hard and the weather resistance decreases.

When the amount of the methacrylic acid alkyl ester as the component (b) used is less than 25% by weight in the ethylenically unsaturated monomer mixture, the hardness of the coating cannot be improved and the coating is easily damaged. On the contrary, if it exceeds 75% by weight, the coating tends to be brittle.

When the amount of the acrylic acid alkyl ester as the component (c) used is less than 10% by weight, the elasticity of the film is impaired.
Vinyl acetate, butadiene, or the like may be used instead to impart elasticity to the coating, but at least 10% by weight of an alkyl acrylate ester in the monomer mixture is used because the water resistance and weather resistance of the coating decrease. On the other hand, if it exceeds 55% by weight, the hardness of the film is too low, which is not preferable.

[Emulsion Polymerization] In emulsion polymerization, an ethylenic monomer mixture is directly added to an aqueous dispersion of a modified urethane prepolymer having a self-emulsifying ethylenic unsaturated bond,
Or add a surfactant, mix and emulsify, then 40-1
It may be carried out at a temperature of 00 ° C using a polymerization initiator, or the self-emulsifying modified urethane prepolymer and the ethylenically unsaturated monomer mixture are added to water containing a surfactant, and the mixture is stirred and mixed. You may do it. After emulsion polymerization,
After lowering the temperature and neutralizing the pH to about 7, as described above, a crosslinking agent is further added for the purpose of forming a stronger and more durable film.

Examples of the cross-linking agent include those having at least two hydrazide groups (-NHNH ₂ ) in the molecule, for example, the following dicarboxylic acid dihydrazides containing 2 to 10 and especially 4 to 6 carbon atoms. Be done. Oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, maleic acid dihydrazide, fumaric acid dihydrazide, and / or itaconic acid dihydrazide, and 2 to 4 carbon atoms having 2 carbon atoms Dihydrazines such as ethylene-1,2-dihydrazine, propylene-1,3-dihydrazine and butylene-
1,4-dihydrazine. And the general formula

[0034]

[Chemical 5]

(In the formula, X is a hydrogen atom or a carboxyl group, Y is a hydrogen atom or a methyl group, and A is each unit of acrylamide, methacrylamide, acrylic ester, methacrylic ester or maleic anhydride. , B is acrylamide, methacrylamide, acrylic acid ester, methacrylic acid ester or another monomer copolymerizable with maleic anhydride, and l, m and n.
Represents a number satisfying the following formulas: 2 mol% ≦ l ≦ 100 mol% 0 mol% ≦ m + n ≦ 98 mol% l + m + n = 100 mol%. A water-soluble acid hydrazide-based polymer represented by
No. 1-35011, JP-A-54-110248.
issue). The cross-linking agent has a mole number of hydrazide groups of 0.0 with respect to the total mole number of carbonyl groups and / or aldehyde groups of the component a in the vinyl monomer mixture constituting the copolymer.
It is mixed in a ratio of 1 to 2.5 equivalents.

100 to 1000 parts by weight of the ethylenically unsaturated monomer mixture, preferably 2 to 100 parts by weight of the modified urethane prepolymer having an ethylenically unsaturated bond.
It is used in a proportion of 00 to 500 parts by weight. If it is less than 100 parts by weight, the alcohol resistance of the obtained coating is not improved so much, and if it exceeds 1000 parts by weight, the gloss of the coating is impaired.

[Polyurethane / Acrylic Resin Aqueous Emulsion] The aqueous emulsion prepared in this manner is, if necessary, a defoaming agent, a film-forming aid, a plasticizer, a thickener, a dye, a pigment, a filler, an antifreezing agent. Clear coat agent, top coat agent, paint, undercoat agent, etc.
Used as an impregnating agent for fibers and paper. In addition to the aqueous emulsion of the present invention, other room temperature crosslinkable aqueous emulsions (Japanese Patent Laid-Open Nos. 54-110248 and 62-72742).
No. 1, Japanese Patent Publication No. 1-15011, etc.) or an aqueous emulsion that does not impair the room temperature crosslinking property can be added within a range that does not impair the original performance.

[0038]

EXAMPLES [Synthesis of Self-Emulsifying Modified Urethane Prepolymer] Production Example 1 The inside of a flask was thoroughly dried under a nitrogen blanket, 250 g of a polyether polyol (average molecular weight 400) and then 235 g of xylylene diisocyanate were charged, and the temperature was adjusted. Was raised to 75-80 ° C. A slight exotherm was observed. The reaction temperature was kept at 75 to 80 ° C., the NCO% of the reaction product was measured, and the reaction was terminated when it was 10.7%. During this time, it took 5 hours.

To the obtained product (120 g), dimethylolpropionic acid (13.4 g) was added, and the reaction was carried out in the same manner as in the previous step. 60 when the viscosity rises and stirring becomes difficult
g of dioxane was added to reduce the viscosity and the reaction was continued.
When the NCO% of the product was 3.2%, 6.5 g of 2-hydroxyethyl methacrylate was added (-OH / -N
CO = 0.5), and the reaction is further continued. The reaction is terminated when the NCO% is 1.5%. During this time, it took 6 hours. The internal temperature was lowered to room temperature, and 30 g of methanol was added.
The solvent was removed and water was added to obtain a self-emulsifying modified urethane prepolymer emulsion having a solid content of 35%.

Production Example 2 The amount of 2-hydroxyethyl methacrylate used was -O.
The same procedure as in Production Example 1 was repeated except that the H / -NCO ratio was changed to 0.85. Gelling occurred and it was not put to practical use.

Production Example 3 The amount of 2-hydroxyethyl methacrylate used was -OH.
The same procedure as in Production Example 1 was repeated except that the / -NCO ratio was changed to 0.2.

[Production of Polyurethane / Acrylic Resin Aqueous Emulsion] Example 1 In a flask, 50 g of water was added to 300 g of the self-emulsifying modified urethane prepolymer emulsion (solid content: 35%) obtained in Production Example 1. After heating this to 80 ° C., 228 g of methyl methacrylate, 72 g of n-butyl acrylate, 5 g of acrylic acid and 10 g of acrolein, and 2 g of polyethylene oxide nonylphenyl ether sulfate sodium salt were added.
An emulsion obtained by dissolving and mixing 16 g of a 5% aqueous solution and 2.6 g of sodium lauryl sulfate in 200 g of water and 50 g of a 3% aqueous solution of potassium persulfate were added in 3 hours, and the mixture was kept at the same temperature for 1 hour to carry out emulsion polymerization. Finished. Then, after cooling to 30 ° C., a 10% aqueous solution of sebacic acid dihydrazide was added to 16
0 g was added to obtain a polyurethane-acrylic resin aqueous emulsion having a minimum film forming temperature of about 35 ° C. and a solid content of about 40%.

Example 2 Methyl methacrylate 2 was placed in a flask containing the self-emulsifying modified urethane prepolymer emulsion obtained in Production Example 1.
After 30 g, 80 g of n-butyl acrylate, and 5 g of acrylic acid were added, emulsion polymerization was carried out in the same manner as in Example 1 to obtain a polyurethane-acrylic resin aqueous emulsion.

Comparative Example 1 Sanker Industries Inc. (SANNCOR I)
NDUSTRIES INC. Polyurethane aqueous dispersion "SunCure Waterborn # 898" (trade name, solid content 35%) manufactured by M.M.A. Co., Ltd. was used as a coating agent.

Comparative Example 2 Sancure # 898 (solid content 35%) and a terpolymer of methyl methacrylate, n-butyl acrylate and acrylic acid (composition ratio shown in Table 1) aqueous emulsion (M
FT50 ° C., solid content 45%) was mixed in the weight ratio of Table 1 to prepare a coating material.

Comparative Example 3 An aqueous emulsion (MFT 50 ° C.) of a terpolymer of methyl methacrylate, n-butyl acrylate and acrylic acid (composition ratio shown in Table 1) was used as a coating material.

Examples 3 to 6 and Comparative Example 4 Tables 1 and 2 show the type and amount of the ethylenically unsaturated monomer and the mixing ratio with the self-emulsifying modified urethane prepolymer.
The same procedure as in Example 1 was performed except that the procedure was changed as described below.

Comparative Example 5 Example 1 was repeated except that the self-emulsifying modified urethane prepolymer obtained in Production Example 3 was used.

[Evaluation Method] The coating materials obtained in the respective examples and comparative examples were evaluated by the following methods. The results are shown in Tables 3 and 4.
All the samples were applied so that a film with a thickness of 100 μm could be obtained and dried at 100 ° C. for 15 minutes.

1) Adhesiveness The film of the sample obtained by the above-mentioned method was squared with a knife (1
00 pieces / cm ² ) and attach the adhesive tape “Cellotape” (trade name) of Nichiban Co., Ltd. to these squares. After pressing the tape, peel it off and leave the number of squares left on the test plate. Was conducted by a test for examining. The result is ○ (95% or more remains), Δ (95-50% remains), × (less than 50% remains)
It was shown in three stages.

2) Water whitening resistance The sample coated on the glass plate by the above-mentioned method was immersed in water at 40 ° C. for 48 hours, and the whitening degree of the coating film was visually observed and evaluated. ○ (no whitening observed), △ (slightly whitening), × (whitening).

3) Durability A 100-micron film was formed on a woodworking board, left for 1 day, then placed in water at a temperature of 20 ° C for 12 hours, then taken out and left in a room at 40 ° C for 12 hours. Hereinafter, the presence or absence of cracks in the film was examined when this repetition was repeated 5 times.
⊚ (no abnormalities), ◯ (10% or less of the whole cracks), Δ (30% or less cracks), × (70% or more cracks are observed).

4) Weather resistance A 100-micron film is formed on a wood board and
After left for a day, the film was left for 500 hours in a weather resistance tester (Sunshine Weatherometer) to check for cracks in the film. ◎ (no abnormality), ◎ (some cracks), × (large crack).

5) Alcohol resistance The sample coated on the glass plate by the above-mentioned method was immersed in alcohol at 20 ° C. for 24 hours, and the dissolution of the coating film and abnormalities of blisters and peeling were visually observed. ○ (no abnormality), △
(Minor abnormalities are seen), × (large abnormalities are seen).

6) Blocking resistance A bleaching cloth is laid on the film obtained by coating and drying on a glass plate by the above-mentioned method, and a load of 500 g is placed on the film, which is left in a constant temperature room at 40 ° C. for one day. After that, the load and the exposure cloth were removed, and the extent of the exposure mark on the film was observed. ○
(No exposure mark), △ (slightly present), × (clearly present).

7) Gloss According to the above method, the gloss of the sample coated on the plate was visually observed. ○ (good gloss), △ (somewhat inferior), ×
(Poor gloss).

[0057]

[Table 1]

[0058]

[Table 2]

[0059]

[Table 3]

[0060]

[Table 4]

[0061]

The polyurethane / acrylic resin aqueous emulsion of the present invention is an emulsion which is a polymer alloy in which a specific polyurethane and an acrylic resin are molecularly bonded, so that the compatibility of both is good and the film has excellent weather resistance. give.

Claims (2)

[Claims] 1. A urethane prepolymer having an isocyanate (--NCO) group at the terminal is added with an ethylenically unsaturated monomer having a hydroxyl group (--OH) group as an isocyanate group of the former prepolymer and a monomer of the latter. Equivalent ratio (-O of hydroxyl group of monomer)
H / -NCO) is reacted at a ratio of 0.3 to 0.6 to obtain a self-emulsifying modified prepolymer having an ethylenically unsaturated bond and an isocyanate group in the molecule. In the presence of 100 parts by weight of polymer solids,
A polyurethane-acrylic resin aqueous emulsion characterized by emulsion-polymerizing an aqueous dispersion of a polymerizable mixture obtained by mixing 100 to 1000 parts by weight of an ethylenically unsaturated monomer containing an acrylic monomer as a main component. Manufacturing method. 2. A urethane prepolymer having an isocyanate (--NCO) group at the terminal is added with an ethylenically unsaturated monomer having a hydroxyl (--OH) group as an isocyanate group of the former prepolymer and a monomer of the latter. Equivalent ratio (-O of hydroxyl group of monomer)
H / -NCO) is reacted at a ratio of 0.3 to 0.6 to obtain a self-emulsifying modified prepolymer having an ethylenically unsaturated bond and an isocyanate group in the molecule. In the presence of 100 parts by weight of polymer solids,
Ethylenically unsaturated monomer mixture of the following (a) to (d) (a) Carbonyl group- or aldehyde group-containing ethylenically unsaturated monomer 1 to 20% by weight (b) Methacrylic acid alkyl ester (of alkyl group Carbon number is 1 to 4) 25 to 75% by weight (c) Acrylic acid alkyl ester (carbon number of alkyl group is 1 to 8) 10 to 55% by weight (d) Other ethylenically unsaturated monomer 0 to 40 Emulsifying an aqueous dispersion of a polymerizable mixture obtained by mixing 100% by weight of 100% by weight (however, the sum of components (a), (b), (c) and (d) is 100% by weight). The carbonyl group- or aldehyde group-containing polyurethane / acrylic resin aqueous emulsion obtained by polymerization was mixed with a hydrazide group (-NH / NH
₂ ) A method for producing a cross-linkable polyurethane / acrylic resin aqueous emulsion, which comprises blending a cross-linking agent having 2 or more of ₂ ).